Plasma processing is a necessary technology in manufacturing a semiconductor device. Along with the recent demand for high integration and high speed of an LSI (Large Scale Integration), a design rule of the semiconductor device forming the LSI requires miniaturization and a semiconductor wafer becomes scaled up. Accordingly, a plasma processing apparatus is required to respond to such miniaturization and scaling up.
However, in a parallel plate type plasma processing apparatus or an inductively coupled plasma processing apparatus which has been conventionally used, an electron temperature of a generated plasma is high, so that plasma damage is inflicted on a micro-device. Further, since a high-density plasma region is locally distributed, it is difficult to uniformly perform plasma processing on a scaled-up semiconductor wafer at a high speed.
Therefore, a RLSA (Radial Line Slot Antenna) microwave plasma processing apparatus capable of uniformly generating a surface wave plasma with a high density and a low electron temperature has attracted attention (see, e.g., Patent Document 1).
In the RLSA microwave plasma processing apparatus, a radial line slot antenna as a planar slot antenna having a plurality of slots formed in a predetermined pattern is provided, as a surface wave plasma generating antenna, at an upper portion of a chamber, and a microwave guided from a microwave generation source is emitted through the slots of the antenna, and radiated into the chamber maintained in a vacuum state through a dielectric microwave transmission plate provided under the antenna. Then, a surface wave plasma is generated in the chamber by the microwave electric field to process an object such as a semiconductor wafer or the like.
Further, there is suggested a plasma processing apparatus including a plurality of microwave emission mechanisms, each having the above-described planar slot antenna, wherein a microwave is divided into a plurality of microwaves and the microwaves emitted from the microwave emission mechanisms are guided into the chamber and spatially combined in the chamber, thereby generating a plasma (see Patent Document 2).